Friday, 31 December 2010

What everybody must know about climate change in Western Australia

The recent record dry weather in southwestern Australia and record wet weather in the “Red” Centre, along with the announcing of the most undesirable coal power projects in the very state most affected by man-made global warming, makes me think that an online “pamphlet” is needed to help people in Western Australia come to grips with how increased CO2, CH4, N2O, and halocarbons have radically altered the state’s climate since the middle 1960s.

Most climate research since these alterations intensified in 1997 has unfortunately been focused on things like the Indian Ocean Dipole and “Asian Haze” that unfortunately do not, as I have emphasised in previous posts, look at the likely cause: that a poleward shift of pressure patterns from global warming has moved the rain belts in such a way that northern and central WA receive more rain and southwestern WA significantly less. Both these features fail to explain key changes:

The Indian Ocean Dipole theory cannot explain why the decline in southern Australian rainfall is concentrated in the autumn when it is ineffective (here)

As I note here, the “Asian Haze” theory fails to model observed increases in rainfall over the Eucla region.

The most logical explanation for the changes is that the Hadley circulation has shifted rapidly poleward and that the monsoon has expanded into the continent

The result of this is that historically humid regions in southwestern Australia are rapidly becoming arid, whilst historically arid regions to the east are becoming monsoonal and humid

There is clear evidence that land clearing is not the cause of the rainfall decline.

Circa 2000 climate models suggested a decline of 60 percent in rainfall over southwestern Australia could be expected by 2050: already, if 2010 rainfall figures are a guide, a decline of 44 percent on pre-global-warming averages has occurred

The probability that the observed decline in rainfall over southwestern Australia is not one hundred percent anthropogenic is minute: Perth’s average wet season rainfall for 2001 to 2010 is four point four two standard deviations below the mean ten-year average pre-global warming. The probability of this occurring by chance is less than one in two hundred thousand!

In the Northern Territory, the ten-year moving average wet season rainfall for the decade ending April 2006 was eight and a half standard deviations above the mean ten-year moving average for the pre-1967 era!

Such a consistently wet spell would have a probability of around one in 1017 (100,000,000,000,000,000) assuming global warming is not the cause! Such a probability is far smaller than the number of years the Earth has existed!

In Forrest in the southeast of Western Australia, the ten-year mean annual rainfall for the decade ending 2006 was five point nine three standard deviations above the mean ten-year moving average before 1967. Such a wet decade would be expected to occur naturally only once every 698,966,090 years!

Paleoclimate data available as early as 1984 suggested very strongly that the mediterranean climate would disappear at carbon dioxide concentrations above 300ppmv. We are already at 400ppmv and under present political and demographic conditions in Australia are likely to be at 700ppmv by 2100.

These same data (and a number of climate experiments done by computer) also suggest that at present carbon dioxide levels the midlatitude arid climates characteristic of areas on the lee side of the mountains present in all mediterranean-climate zones (the Darling Scarp and Stirling Range do this with Western Australia) would also disappear. This result is in complete agreement with observed rainfalls in Forrest.

There is no likelihood primary productivity gains in the state’s east will offset the disappearance of farming in the southwest from desertification. This is because the already-impoverished soils will lose what nutrients they have from the more humid weather

Biodiversity losses from the desertification of southwestern Australia could, even in the short-term future, exceed anything that has been seen in the world. The region contains 45 percent of Australia’s native plant species, most of which occur nowhere else and none of which can survive in an arid or monsoonal climate.

These biodiversity losses could already occur in the humid karri forest country though fires this year. Not one station in southwestern WA received even 800 mm of rain during 2010, yet the generally accepted minimum for karri is 900 mm and that for yellow tingle and red tingle even higher.

If we presume that 2010 rainfalls are the absolute maximum likely to occur in this area in the future, we can say that these magnificent tall trees have already lost all suitable habitat to global warming and that only a rapid reduction in carbon dioxide levels can save them.

Australia would need therefor to eliminate by law all fossil fuel energy and restrict itself to what renewable energy can provide immediately.

It would need to outlaw at least private cars and coal-fired energy and the revegetate all areas where these fuels occur as National Parks or Aboriginal Reserves.

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About Me

A former student at Melbourne and RMIT who hoped to get a job in librarianship by 2009.
Be wary that I tend to have very specialised interests and often do not want too general questions.
I enjoy reading about many difficult topics and would love to be able to discuss them with people who know more about them than people around me.
I have a particular love for lists of “best” or “worst” music or books, and love statistics a great deal.